Electronic States

Question 1

The interaction that mixes a ground state into a particular excited state must transform as the_______.

Answer 1

Direct product of the symmetry of the two states.

Γ_gs ⊗ Γ_ex

(First step in determining if spin-orbit coupling mixes an excited state into an ground state.)

Question 2

Relaxation of an excited state to a ground state that emits a photon without a change in spin multiplicity.

Answer 2

Fluorescence​​​

Question 3

This process occurs when an excited molecule or atom relaxes to a lower energy state (possibly the ground state) through emission of a photon.

Answer 3

Luminescence ​​​

Question 4

Relaxation of an excited state to a ground state that emits a photon with a change in spin multiplicity.​

Answer 4

Phosphorescence​

Question 5

A process where there is a conversion between electronic states of different multiplicity.

Answer 5

Intersystem Crossing

Question 6

In order that the spin-coupling operator mix a ground state into a particular excited state, what is required?

Answer 6

• The energy difference between the two states must be small
• The direct product of the two states must contain the irreducible representation of the spin-coupling operator.

Question 7

A phenomenon that arises in paramagnetic systems with multiple unpaired electrons (i.e., S > 1/2) as a result of both spin–spin coupling (SSC) and spin–orbit coupling (SOC) interactions

Answer 7

Zero-field splitting

Question 8

The spin-orbit coupling operator directly splits the degeneracy of a group state without resorting to a distortion.

Answer 8

In-state orbital angular momentum

Question 9

When the spin-orbit coupling operator cannot split degeneracy of a state and requires coupling to a low lying excited state and a molecular distortion.

Answer 9

Out-of state orbital angular momentum

Question 10

The interaction between electronic and nuclear vibrational motion that leads to d-d transition becoming more Laporte​ allowed

Answer 10

Vibronic Coupling

Question 11

A type of electronic transition that involves a transition from metal dominated MOs in the ground state to ligand dominated MOs in the excited state.

Answer 11

Metal-Ligand Charge Transfer

Question 12

A type of electronic transition between two metal sites differing only in oxidation state

Answer 12

Intervalence charge transfer

Question 13

A type of electronic transition that involves a transition from ligand dominated MOs in the ground state to metal dominated MOs in the excited state

Answer 13

Ligand-Metal Charge Transfer

Question 14

What non-radiative exchange mechanism is shown below?

Answer 14

Triplet-Triplet Dexter Energy Transfer

Question 15

What non-radiative exchange mechanism is shown below?

Answer 15

Singlet-Singlet Dexter Energy Transfer

Question 16

What non-radiative exchange mechanism is shown below?

Answer 16

Singlet-Singlet Foster Energy Transfer

Question 17

The characteristic of f-f transitions in Lanthanide:

Answer 17

• Characteristic wavelengths
• Narrow line widths
• Millisecond lifetimes (Long lifetimes)
• Laporte forbidden

Question 18

Which electronic transition will have the higher value of epsilon in the d² metal complex?

⁴A_2g —-> ²E_g

⁴A_2g —-> ⁴T_2g

Answer 18

⁴A_2g —-> ⁴T_2g

⁴A_2g —-> ²E_g is spin forbidden

Question 19

Electronic transitions between states with different spin multiplicities.

Answer 19

Spin Forbidden

Question 20

How does the spin-orbit coupling operator transform in a particular point group?

Answer 20

R_x R_y R_z (infinitesimal rotations)

Question 21

How many microstate does the ³F term symbol contain?

Answer 21

21

—————————————————————–

F —> L=3 —> 2*(3)+1=7

7*3=21

Question 22

The degeneracy of the |Ms> sublevels of the ground state is lifted in the absent of a magnetic field.

Answer 22

Spin-Orbit Coupling

Question 23

Ground state will have the _____spin multiplicity.

Answer 23

Largest

If thesame spin multiplicity, then the GS will have the highest value of L.

Question 24

In O_h and D_4h , all d orbitals are gerade and so too are the states arising from their d configurations. Thus, their electronic transitions between them are________.

Answer 24

Laporte Forbidden​

Question 25

## Footnote **If a system is centrosymmetric, electronic transitions between states with the same inversion symmetry (g --\> g, u --\> u) are forbidden, but transitions between states of different inversion symmetry** **(g --\> u, u --\>g) are allowed.**

Answer 25

**Laporte's Rule​**

Question 26

**Idenifty the gaseous ground state term symbol for a d² metal ion.**

Answer 26

³**F**

Question 27

**Idenifty the strong field region of the** **d⁵ Tanabe-Sugano Diagram.**

Answer 27

## Footnote ***Low Spin Configurations***

Question 28

**Idenifty the weak field region of the** **d⁵ Tanabe-Sugano Diagram.**

Answer 28

## Footnote ***High Spin Configurations***

Question 29

**What is the symbol for the rhombic ZFS component​?**

Answer 29

**E parameter**

Question 30

**What is the symbol for the axial ZFS component​?**

Answer 30

**D parameter**

Question 31

**Idenifty the states that are involved in an avoided crossing** **in the reaction coordinate below.**

Answer 31

## Footnote **The a₁ states**

Question 32

## Footnote **Non-Crossing Rule**

Answer 32

**Two states of the same symmetry and spin multiplicity cannot cross. Instead, they will admix in order to cause an avoided crossing.​**

Question 33

Determine M_L and M_S vaules of the free ions term below: **²D**

Answer 33

**D**: L=2 M_L={-2,-1,0,1,2} 2S+1=**2** --\> S=1/2 --\> M_S= {1/2,-1/2}

Question 34

**^BA_c**

Answer 34

**A: Total orbital angular momentum *(L)*** **B: *Spin multiplicity (2S+1)*** **C: Total angular momentum (J)**